1. Field of the Invention
The present invention relates to a temperature measurement apparatus used for a heat treatment apparatus that performs a heat treatment to a substrate mounted on a rotating table while rotating the substrate by rotating the rotating table, a method of measuring a temperature profile, a recording medium and a heat treatment apparatus.
2. Description of the Related Art
For a heat treatment apparatus, an apparatus including a process container in which a rotating table is provided, is known. In this heat treatment apparatus, plural semiconductor wafers (which are examples of substrates, and hereinafter simply referred to as wafers) are mounted on the rotating table along a rotating direction. Further in this heat treatment apparatus, a gas supply unit that supplies process gas is provided to extend in a radius direction of the rotating table. Further, within this heat treatment apparatus, a heater for heating the wafers is provided and layers are deposited on the wafers by discharging the gas from the gas supply unit while the wafers are heated and the rotating table is rotated.
In such a heat treatment apparatus, a test to detect whether the wafers are heated to appropriate temperature is performed. This test is performed by using a wafer for measurement provided with a thermocouple, where the thermocouple is connected to an external detection device outside of the process container through a wiring. For the test, for example, after an operator places the wafers for measurement at areas of the rotating table for which wafers are to be mounted, the temperature of the heater is raised. Then, the temperature of the wafers for measurements is measured by the thermocouples. As the wiring is connected to each of the wafers for measurement as described above, the rotating table is kept immobilized during this test.
However, when forming films or layers, a temperature profile is generated by a placement of the heater at an area where the rotating table is rotated, and the wafers pass through such an area where the temperature profile is generated. Further, the wafers may be influenced by temperature of the discharged gas. Although the above described test is performed, the temperature of the wafers when forming the films cannot be accurately measured in such situations. Further, for a safety of the operator, in the above test, the temperature of the heater is raised after the wafers for measurement are placed on the rotating table. However, for an actual operation, a group of wafers may be introduced into the process container at timing when the process container is still heated after a previous group of wafers to which a process is performed is taken out from the process container. Therefore, a process of raising the temperature of the wafers in an actual process cannot be detected by the above described test.
Further, in order to detect the temperature profile on whole surfaces of the wafers, it is necessary to prepare an increased number of thermocouples to increase accuracy precision. However, there is a limitation in the number of thermocouples provided to each of the wafers for measurement because the space is limited. Therefore, there is a problem that the temperature profile cannot be accurately detected on the whole surfaces of the wafers.
Patent Document 1 discloses a method of measuring a temperature profile of a surface of a substrate which is mounted on a rotary susceptor provided in a reactor for vapor deposition of a thin layer. In this method, the temperature profile of the surface of the substrate is measured by continuously measuring temperature of the surface of the substrate mounted on the rotary susceptor by a temperature measurement unit provided at a predetermined position, analyzing a path of measured points of the substrate, which vary in accordance with a rotation of the susceptor, based on information of a rotating speed of the susceptor, and coordinating the temperature measured by the temperature measurement unit with the measured points of the substrate based on the analyzed path.
However, by the method disclosed in Patent Document 1, as the measured positions are determined based on the rotation of the substrate, it is difficult to regularly measure plural areas of the surface of the substrate.